1. Haloalkanes, Alkenes, and Alkynes Alkenes and Alkynes Geometric Isomers of Alkenes Addition Reactions

2. Saturated and Unsaturated Compounds Saturated compounds (alkanes) have the maximum number of hydrogen atoms attached to each carbon atom Unsaturated compounds have fewer hydrogen atoms attached to the carbon chain than alkanes Unsaturated compounds contain double or triple bonds

3. Alkenes  Carbon-carbon double bonds  Names end in -ene H 2 C=CH 2 ethene (ethylene) H 2 C=CH-CH 3 propene (propylene) cyclohexene

4. Alkynes  Carbon-carbon triple bonds  Names end in -yne HC  CHethyne(acetylene) HC  C-CH 3 propyne

5. Naming Alkenes and Alkynes When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond. 1 2 3 4 CH 2 =CHCH 2 CH 3 1-butene CH 3 CH=CHCH 3 2-butene CH 3 CH  CHCH 3 2-butyne

6. Learning Check Write the IUPAC name for each of the following unsaturated compounds: A.CH 3 CH 2 C  CCH 3 CH 3 B. CH 3 C=CHCH 3 C.

7. Solutions Write the IUPAC name for each of the following unsaturated compounds: A.CH 3 CH 2 CH=CHCH 3 2-pentyne CH 3 B. CH 3 C=CHCH 3 C. 2-methyl-2-butene 3-methylcyclopentene

8. Cis and Trans Isomers  Double bond is fixed  Cis/trans Isomers are possible CH 3 CH 3 CH 3 CH = CH CH = CH cis trans CH 3

9. Hydrogenation Adds a hydrogen atom to each carbon atom of a double bond H H H H Ni H–C=C–H + H 2 H–C–C–H H H ethene ethane

10. Products of Hydrogenation Adding H 2 to vegetable oils produces compounds with higher melting points Margarines Soft margarines Shortenings (solid)

11. Learning Check What is the product of adding H 2 (Ni catalyst) to 1-butene?

12. Solution What is the product of adding H 2 (Ni catalyst) to 1-butene? Ni CH 2 =CHCH 2 CH 3 + H 2 CH 3 CH 2 CH 2 CH 3

13. Adding Halogens Halogens also add to the double bond of an alkene. H 2 C  CH 2 + Cl 2

14. Learning Check Write the product of the following addition reactions: CH 3 CH=CHCH 3 + H 2

15. Solution Write the product of the following addition reactions: CH 3 CH=CHCH 3 + H 2 CH 3 CH 2 CH 2 CH 3

16. Unsaturated Fatty Acids Fatty acids in vegetable oils are omega-6 acids (the first double bond occurs at carbon 6 counting from the methyl group) A common omega-6 acid is linoleic acid CH 3 CH 2 CH 2 CH 2 CH 2 CH=CHCH 2 CH=CH(CH 2 ) 7 COOH 6 linoleic acid, a fatty acid

17. Trans Fats  In vegetable oils, the unsaturated fats usually contain cis double bonds.  During hydrogenation, some cis double bonds are converted to trans double bonds (more stable) causing a change in the fatty acid structure  If a label states “partially” or “fully hydrogenated”, the fats contain trans fatty acids.

18. Trans Fats  In the US, it is estimated that 2-4% of our total Calories is in the form of trans fatty acid.  trans fatty acids behave like saturated fatty acids in the body.  Several studies reported that trans fatty acids raise LDL-cholesterol. Some studies also report that trans fatty acid lower HDL- cholesterol  The trans fatty acids controversy will continue to be debated.

19. Fats and Atheroschlerosis Inuit people of Alaska have a high fat diet and high blood cholesterol levels, but a very low occurrence of atherosclerosis and heart attacks. Fat in the Intuit diet was primarily from fish such as salmon, tuna and herring rather than from land animals (as in the American diet).

20. Omega-3 Fatty Acids Fatty acids in the fish oils are mostly the omega-3 type (first double bond occurs at the third carbon counting from the methyl group). linolenic acid 18 carbon atoms CH 3 CH 2 CH=CHCH 2 CH=CHCH 2 CH=CH(CH 2 ) 7 COOH  eicosapentaenoic acid (EPA) 20 carbon atoms CH 3 CH 2 (CH=CHCH 2 ) 5 (CH 2 ) 2 COOH

21. Atherosclerosis Plaques of cholesterol adhere to the walls of the blood vessels Blood pressure rises as blood squeezes through smaller blood vessels Blood clots may form Omega-3 fatty acids decrease the “sticking” of blood platelets (fewer blood clots) Omega-3 fatty acids can increase bleeding time

22. Learning Check (1) True or (2) False A. ____ There are more unsaturated fats in vegetable oils. B. ____ Vegetable oils have more omega-3 oils than found in fish. C. ____ Hydrogenation of oils converts some cis-double bonds to trans- double bonds. D. ____ Animal fats have more saturated fats.

23. Solution (1) True or (2) False A. _T__ There are more unsaturated fats in vegetable oils. B. _F__ Vegetable oils have more omega-3 oils than found in fish. C. _T__ Hydrogenation of oils converts some cis-double bonds to trans- double bonds. D. _T__ Animal fats have more saturated fats.